Accurate Gravities of F, G, and K Stars from High Resolution Spectra Without External Constraints
2015 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 805, no 2, 126Article in journal (Refereed) Published
We demonstrate a new procedure to derive accurate and precise surface gravities from high resolution spectra without the use of external constraints. Our analysis utilizes Spectroscopy Made Easy with robust spectral line constraints and uses an iterative process to mitigate degeneracies in the fitting process. We adopt an updated radiative transfer code, a new treatment for neutral perturber broadening, a line list with multiple gravity constraints and separate fitting for global stellar properties and abundance determinations. To investigate the sources of temperature dependent trends in determining log g noted in previous studies, we obtained Keck HIRES spectra of 42 Kepler asteroseismic stars. In comparison to asteroseismically determined log g our spectroscopic analysis has a constant offset of 0.01 dex with a rms scatter of 0.05 dex. We also analyzed 30 spectra which had published surface gravities determined using the a/R-* technique from planetary transits and found a constant offset of 0.06 dex and rms scatter of 0.07 dex. The two samples covered effective temperatures between 5000 and 6700 K with log g between 3.7 and 4.6.
Place, publisher, year, edition, pages
2015. Vol. 805, no 2, 126
asteroseismology, methods: data analysis, stars: fundamental parameters, stars: solar-type, techniques: spectroscopic
IdentifiersURN: urn:nbn:se:uu:diva-258779DOI: 10.1088/0004-637X/805/2/126ISI: 000356715400041OAI: oai:DiVA.org:uu-258779DiVA: diva2:842429